feat(front): selecteur couple enfant-nounou (#167)

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/lib/screens/home/parent_screen/ParentDashboardScreen.dart

@@ -1,10 +1,14 @@
 import 'package:flutter/material.dart';
+import 'package:p_tits_pas/models/couple_garde.dart';
 import 'package:p_tits_pas/models/user.dart';
 import 'package:p_tits_pas/services/auth_service.dart';
+import 'package:p_tits_pas/services/couple_garde_service.dart';
+import 'package:p_tits_pas/widgets/quotidien/couple_selector_bandeau.dart';
 import 'package:p_tits_pas/widgets/quotidien/quotidien_shell.dart';
 import 'package:p_tits_pas/widgets/quotidien/quotidien_theme.dart';
 
 /// Tableau de bord parent — coquille 3 colonnes quotidien (#166).
+/// Colonne gauche : sélecteur de couple enfant–nounou (#167).
 /// Métier cartes / blog / messagerie : tickets C/D/E.
 class ParentDashboardScreen extends StatefulWidget {
   const ParentDashboardScreen({super.key});
@@ -17,10 +21,16 @@ class _ParentDashboardScreenState extends State<ParentDashboardScreen> {
   QuotidienNavSection _section = QuotidienNavSection.liaison;
   AppUser? _user;
 
+  List<CoupleGarde> _couples = const [];
+  String? _selectedCoupleId;
+  bool _couplesLoading = true;
+  String? _couplesError;
+
   @override
   void initState() {
     super.initState();
     _loadUser();
+    _loadCouples();
   }
 
   Future<void> _loadUser() async {
@@ -28,6 +38,52 @@ class _ParentDashboardScreenState extends State<ParentDashboardScreen> {
     if (mounted) setState(() => _user = user);
   }
 
+  Future<void> _loadCouples() async {
+    setState(() {
+      _couplesLoading = true;
+      _couplesError = null;
+    });
+    try {
+      final res = await CoupleGardeService.getCouplesGarde();
+      if (!mounted) return;
+      setState(() {
+        _couples = res.couples;
+        _selectedCoupleId = res.coupleCourant?.id;
+        _couplesLoading = false;
+      });
+    } catch (e) {
+      if (!mounted) return;
+      setState(() {
+        _couplesError = e.toString().replaceFirst('Exception: ', '');
+        _couplesLoading = false;
+      });
+    }
+  }
+
+  Future<void> _selectCouple(CoupleGarde couple) async {
+    if (couple.id == _selectedCoupleId) return;
+    // Optimiste : on bascule tout de suite, l'API persiste ensuite.
+    setState(() => _selectedCoupleId = couple.id);
+    try {
+      final res = await CoupleGardeService.definirCoupleCourant(couple.id);
+      if (!mounted) return;
+      setState(() {
+        _couples = res.couples;
+        _selectedCoupleId = res.coupleCourant?.id ?? couple.id;
+      });
+    } catch (e) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text(
+            'Impossible de changer de garde : '
+            '${e.toString().replaceFirst('Exception: ', '')}',
+          ),
+        ),
+      );
+    }
+  }
+
   String get _displayName {
     final n = _user?.fullName.trim() ?? '';
     if (n.isNotEmpty) return n;
@@ -52,11 +108,13 @@ class _ParentDashboardScreenState extends State<ParentDashboardScreen> {
       onProfileTap: () => _soon('Profil'),
       onSearchAmTap: () => _soon('Recherche AM'),
       onSettingsTap: () => _soon('Paramètres'),
-      leftColumn: const QuotidienColumnPlaceholder(
-        title: 'Cartes',
-        subtitle:
-            'Couple enfant–nounou et flux de cartes\n(à brancher — tickets #167 / #173).',
-        icon: Icons.style_outlined,
+      leftColumn: _LeftColumn(
+        couples: _couples,
+        selectedCoupleId: _selectedCoupleId,
+        loading: _couplesLoading,
+        error: _couplesError,
+        onRetry: _loadCouples,
+        onCoupleSelected: _selectCouple,
       ),
       centerColumn: const QuotidienColumnPlaceholder(
         title: 'Blog',
@@ -81,3 +139,51 @@ class _ParentDashboardScreenState extends State<ParentDashboardScreen> {
     );
   }
 }
+
+/// Colonne gauche : bandeau couple (#167) puis flux de cartes (#173 à venir).
+class _LeftColumn extends StatelessWidget {
+  final List<CoupleGarde> couples;
+  final String? selectedCoupleId;
+  final bool loading;
+  final String? error;
+  final VoidCallback onRetry;
+  final ValueChanged<CoupleGarde> onCoupleSelected;
+
+  const _LeftColumn({
+    required this.couples,
+    required this.selectedCoupleId,
+    required this.loading,
+    required this.error,
+    required this.onRetry,
+    required this.onCoupleSelected,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.all(14),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.stretch,
+        children: [
+          CoupleSelectorBandeau(
+            couples: couples,
+            selectedCoupleId: selectedCoupleId,
+            loading: loading,
+            errorMessage: error,
+            onRetry: onRetry,
+            onCoupleSelected: onCoupleSelected,
+          ),
+          const SizedBox(height: 14),
+          const Expanded(
+            child: QuotidienColumnPlaceholder(
+              title: 'Cartes',
+              subtitle:
+                  'Absences, congés AM, sorties à valider\n(à brancher — ticket #173).',
+              icon: Icons.style_outlined,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}